Conventional jet black automotive pigments are subject to significant variations in jetness. By jetness is meant a true blue-black color with depth and clarity totally void of haziness and/or conflicting undertones of red, yellow or brown. The color development of a high color carbon black is dependant on the vehicle used to disperse the pigment (e.g., of dispersing vehicles, thermosetting acrylic copolymers, butylated melamines, polyester resins, alkyl resins, polymethanes, etc.). The structure and immense surface area of the high color carbon blacks require a very mobile (good wetting) vehicle which will extend itself to wet and encapsulate the pigment (individual particles and sub-micron agglomerates) during the dispersion process. Not all vehicles are capable of being extended to fully wet and encapsulate these pigments resulting in varying degrees of color development (jetness). The particular dispersion vehicle selection is governed by the finished enamel system, and optimum color development (jetness, clarity, depth) cannot always be obtained. The dispersion method (steel ball mil, attritor, etc.) requires formulation changes to optimize the efficiency of the specific equipment. However, the dispersion method is secondary to the vehicle of optimum jetness and depth. Substitution of the dispersion vehicle to enable such jet black automotive pigments to be compatible with various automotive paints systems (e.g., thermosetting acrylics, urethanes, thermoplastic acrylics, etc.) and/or altering the dispersion methods(e.g., steel ball mill, attritor, etc.) will result in variations in jetness ranging from deep blue-black to milky red-brown. As can be appreciated, such variations in predictability for jet black automotive pigments is not a desirable feature.
All such pigments, which develop color and transparency as a product of the dispersing procedure also generally are lacking in chroma and purity of color. Since the pigment agglomerates cannot be reduced to discrete particles, gloss and distinctness of image are adversely affected. Furthermore, convention dyes also have a tendency to naturally "bleed" from the polymer systems resulting in a gradual change of color of lessening jetness.
Accordingly, what is needed in this art is an improved coating composition and coating system of consistent color regardless of the dispersion method or vehicle used which can provide durable, universal jetness.